Trace each dedicated outdoor air unit from the schedule into its applicability basis, casing leakage class, energy recovery effectiveness, filter rating, and controls protocol, then confirm the unit’s scope boundary with the ductwork and sensors it connects to before treating a schedule entry as complete.
Assemble the review package
Gather the mechanical equipment schedule, outdoor-air ventilation calculations, the roof or mechanical-room mounting detail, the direct-digital-control point list, and the issued dedicated outdoor air systems specification. This section covers only the DOAS air-handling equipment and its internal components; the ductwork and sensors it connects to are specified elsewhere. Review one unit completely before assuming a similar schedule row shares the same energy recovery type and controls protocol.
WBDG publishes UFGS 23 74 33: Dedicated Outdoor Air Systems (DOAS) as a public guide-specification reference (accessed September 26, 2026). Use your project’s issued specification and amendments for the actual comparison; the guide specification does not automatically govern your project. The checklist below is an original suggested review workflow, not a reproduction of the UFGS requirements.
Eight checks to run against the issued set
Use one record per location or system. The CSV contains the same eight prompts plus fields for source revisions, observed evidence, the review owner, the decision, and closure references.
| Check | Sources to compare | Question to resolve |
|---|---|---|
| Applicability threshold | Ventilation airflow calculation + specified 354 L/s (750 cfm) DOAS applicability basis | Does the unit’s scheduled outdoor-air volume actually exceed the threshold that triggers a DOAS unit under UFC 3-410-01 and ASHRAE 62.1, rather than a smaller ventilation load that a unitary or air handling unit could serve instead? |
| Scope boundary with ductwork and sensors | DOAS schedule note + ductwork and controls drawings | Since this section covers the air-handling equipment and internal components only, do the ductwork and sensor requirements the unit depends on actually appear in the ductwork and controls sections rather than being assumed as part of the DOAS submittal? |
| Casing leakage class | Schedule static-pressure basis + specified Class A, B, or C cabinet leakage limit | Does the specified cabinet class and its 1 percent maximum leakage limit match the actual operating static pressure shown for that unit? |
| Energy recovery effectiveness and cross-contamination | Space use (such as a laboratory or isolation space) + specified energy recovery effectiveness and EATR/OACF documentation | Where the schedule specifies a rotary wheel or other energy recovery device with a documented cross-contamination percentage, has the equipment schedule’s EATR/OACF entry actually been checked against a space that cannot tolerate any exhaust-to-supply crossover? |
| Filter rating assignment | Schedule filter note + specified MERV rating and test basis | Does the specified MERV rating (8, 13, 15, or 16 under ASHRAE 52.2) match the filtration level called for by the space the unit serves, rather than a default carried over from a different unit? |
| Refrigerant safety compliance | Refrigerant-containing component location + specified ANSI/ASHRAE 15 and 34 compliance | Do the refrigerant circuit and coil components identified in the schedule reference compliance with ANSI/ASHRAE 15 and 34, and are CFC refrigerants excluded from any heat-pipe or frost-control component? |
| Gas-fired heating section coordination | Available fuel source + specified direct or indirect gas-fired heating section | Where a gas-fired heating section is specified, does the direct or indirect type match the available fuel source and the combustion-air and venting provisions shown on the mechanical drawings? |
| Controls protocol interface | Specified BACnet or LonWorks tailoring option + the building’s existing direct-digital-control system | Does the unit’s specified control-system interface protocol match the protocol already used by the building’s direct-digital-control system, consistent with how the same tailoring option is handled on unitary HVAC equipment? |
Worked example: a rotary wheel scheduled for a no-crossover space
Illustrative example: a DOAS unit serving a laboratory suite is scheduled with a rotary energy recovery wheel because it is the manufacturer’s standard option, while the space’s design intent calls for no crossover between exhaust and supply air. A rotary wheel carries a documented cross-contamination percentage between airstreams, which the equipment schedule’s EATR/OACF entry does not address for this particular space.
Confirm the space’s actual crossover tolerance with the mechanical engineer, and if a no-crossover requirement stands, ask whether a run-around coil or another energy recovery type without airstream crossover should replace the rotary wheel. Recheck the unit’s casing class and controls protocol for the corrected selection before closing the item.
Avoid a false conflict
A DOAS unit that satisfies the applicability threshold and carries an energy recovery device does not by itself confirm the cross-contamination basis was checked against the space it serves; a manufacturer’s standard energy recovery selection can be unsuitable for a specific ventilation intent even when its effectiveness percentage looks acceptable.
When requirements disagree, follow the project’s document-control and clarification process. Do not assume that drawings always override specifications, or the reverse. Identify the exact sources and request an authorized decision.
Close the issue across the affected documents
Record the location or tag, drawing and specification references, issue dates, observed difference, and the decision needed. Assign an owner and keep the item open until the response identifies the governing requirement. Check the revised drawings and specification references together; a response email alone may leave the issued package inconsistent.
For the overall process, use the guide to drawing and specification conflicts. Mark an inapplicable checklist row with a reason, and distinguish a verified correction from a question that still needs design information.
Where Groundbook fits
Groundbook’s drawing and specification review helps investigate potential disagreements in the documents you supply. Include the relevant specification sections and drawing references, then verify the cited evidence with the responsible reviewers before acting on a finding.